The search a week ago related to an alleged historical sex offence in Sheffield, which the singer denies.

BBC cameras and a reporter were outside the gates to Sir Cliff's property in Sunningdale, Berkshire when eight police officers arrived.

The BBC has received hundreds of complaints related to its reporting.

Following the search, former policing minister Nick Herbert said police and the BBC had "serious questions to answer" about how journalists knew of the operation in advance.

'Significant story'

In a letter to Home Affairs Select Committee chairman Keith Vaz, Lord Hall said: "I believe that BBC journalists have acted appropriately in pursuing this story.

"As you rightly say, the media has a right to report on matters of public interest.

"Sir Cliff Richard is one of the most successful British entertainers of all time and has been a prominent public figure for several decades.

"Investigations into historic sex abuse cases have - and will continue to have - a profound impact on the lives of well-known individuals and the standing of public institutions.

"The disclosure of a sex abuse allegation against Sir Cliff Richard and the police search of his property was clearly a significant story and the BBC was not alone in providing extensive coverage."

South Yorkshire Police has said it was contacted some weeks ago by a BBC reporter "who made it clear he knew of the existence of an investigation" and "it was agreed that the reporter would be notified of the date of the house search in return for delaying publication of any of the facts".

The force complained to Lord Hall and said the BBC appeared to have broken its own editorial guidelines.

Protecting sources

Mr Vaz had earlier written to Lord Hall and South Yorkshire Police Chief Constable David Crompton asking them to explain how the BBC knew of the search in advance and what agreement was struck between their organisations.

Asking for a reply by midday on Friday, he said he may ask both men to give evidence in person to his committee when Parliament returns from recess in September.

In his reply, Lord Hall said protecting sources was a "key principle for all journalism", explaining that "for that reason the BBC will not be providing details about the source".

He added: "I fully understand that a core part of the work of your committee is to scrutinise the work of the police, but I am sure you also appreciate that the BBC's editorial independence, as guaranteed by the BBC Charter, is something we take very seriously and is highly valued by the British public; as such it would not be appropriate to elaborate on detail of our editorial processes."

'Fair and impartial'

The allegation against Sir Cliff relates to an assault claim at an event featuring US preacher Billy Graham at Bramall Lane in Sheffield in 1985, the BBC understands.

The BBC has previously confirmed that its source relating to the police investigation was not the South Yorkshire force.

In a separate statement issued after the search of Sir Cliff's home, the BBC said the matter had been reported in a "fair and impartial manner".

The BBC had made contact with Sir Cliff's agent as soon as the search started, which it said had been "well before" the story was broadcast, and "due prominence" was given to the singer's denial of the allegation.